zmq

getchaintips
Return information about all known tips in the block tree, including the main chain as well as orphaned branches.
Result:
[
{
"height": xxxx, (numeric) height of the chain tip
"hash": "xxxx", (string) block hash of the tip
"branchlen": 0 (numeric) zero for main chain
"status": "active" (string) "active" for the main chain
},
{
"height": xxxx,
"hash": "xxxx",
"branchlen": 1 (numeric) length of branch connecting the tip to the main chain
"status": "xxxx" (string) status of the chain (active, valid-fork, valid-headers, headers-only, invalid)
}
]
Possible values for status:
1. "invalid" This branch contains at least one invalid block
2. "headers-only" Not all blocks for this branch are available, but the headers are valid
3. "valid-headers" All blocks are available for this branch, but they were never fully validated
4. "valid-fork" This branch is not part of the active chain, but is fully validated
5. "active" This is the tip of the active main chain, which is certainly valid
Examples:
> bitcoin-cli getchaintips
> curl --user myusername --data-binary '{"jsonrpc": "1.0", "id":"curltest", "method": "getchaintips", "params": [] }' -H 'content-type: text/plain;' http://127.0.0.1:8332/